The present invention relates to switches and more specifically to elastomer switches.
Gold-plated contacts are offered on many mechanical switches. Elastomer or membrane switches have also utilized gold-plated contacts. In a typical elastomer switch used in a high reliability situation, a gold-plated contact attached to an elastomer material is forced into physical contact with a gold-plated contact or contacts on a printed circuit board (PCB). The switch contacts have been plated with gold because gold is a good conductor and generally does not corrode. Gold-plated contacts provide a relatively low resistance path until arcing or wear degrades the gold-plated contacts. However, utilizing gold-plated contacts increases the cost of a switch, as gold is a relatively expensive material and requires additional manufacturing processing steps. As a result, switches with carbon coated contacts have increasingly been utilized as an alternative to switches with gold plated contacts. However, carbon switches suffer from higher and less repeatable contact resistance. On the other hand, while gold contacts are generally adversely affected by the wave soldering process, carbon contacts are generally not adversely affected.
An embodiment of the present invention is directed to a switch assembly. The switch assembly includes a plurality of electrical devices and a plurality of user activated switches. The plurality of electrical devices each include a control terminal. Each of the plurality of electrical devices causes a different distinguishable output to be provided when a control signal is asserted on its control terminal. The user activated switches include carbon-coated contacts. Each of the user activated switches is associated with one of the plurality of electrical devices. Asserting one of the user activated switches, causes a control signal to be provided to the control terminal of one of the plurality of electrical devices.
In the preferred embodiment, the elastomer switches are incorporated within a rear view mirror. An advantage of the present invention is that gold can be eliminated as a contact material, thus reducing cost without introducing undesirable resistance into a circuit path.
These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings.